The present invention relates to the field of steering assemblies used for downhole directional drilling. The prior art discloses directional drilling drill bit assemblies.
U.S. Pat. No. 5,553,678 to Barr et al., which is herein incorporated by reference for all that it contains, discloses a modulated bias unit is provided for controlling the direction of drilling of a rotary drill bit when drilling boreholes in subsurface formations. The unit comprises a plurality of hydraulic actuators spaced apart around the periphery of the unit and having movable thrust members hydraulically displaceable outwardly for engagement with the formation of the borehole being drilled. Each actuator has an inlet passage for connection to a source of drilling fluid under pressure and an outlet passage for communication with the annulus. A selector control valve connects the inlet passages in succession to the source of fluid under pressure, as the unit rotates, and a choke is provided to create a pressure drop between the source of fluid under pressure and the selector valve. A further choke is provided in the outlet passage from each actuator unit. The actuators and control valve arrangements may take a number of different forms.
U.S. Pat. No. 4,416,339 to Baker et al., which is herein incorporated by reference for all that it contains, discloses a mechanism and method for positive drill bit guidance during well drilling operations. The guidance device includes a control arm or paddle which, due to hydraulic pressure, pivots to steer the drill bit towards its target area. As the paddle applies pressure to the wall of the well, the drill bit is then turned from the contacted area of the well wall in the desired direction.
U.S. Pat. No. 5,582,259 to Barr et al., which is herein incorporated by reference for all that it contains, discloses a modulated bias unit, for controlling the direction of drilling of a rotary drill bit when drilling boreholes in subsurface formations, comprises a number of hydraulic actuators spaced apart around the periphery of the unit. Each actuator comprises a movable thrust member which is hydraulically displaceable outwardly and a formation-engaging pad which overlies the thrust member and is mounted on the body structure for pivotal movement about a pivot axis located to one side of the thrust member. A selector control valve modulates the fluid pressure supplied to each actuator in synchronism with rotation of the drill bit so that, as the drill bit rotates, each pad is displaced outwardly at the same selected rotational position so as to bias the drill bit laterally and thus control the direction of drilling. The pivot axis of the formation-engaging member is inclined to the longitudinal axis of rotation of the bias unit so as to compensate for tilting of the bias unit in the borehole during operation.